This invention relates to a hydraulic coupling device for connection to a multi-line hose constituted by a plurality of hydraulic conduits bunched together. The invention is particularly useful in the hydraulic distribution systems used in underground mine workings, particularly for hydraulic advanceable mine roof support assemblies and other hydraulic appliances.
Systems are known in which numerous hydraulic conduits are bunched together to form multi-line hoses. Multi-line hoses are interconnected by means of pairs of complementary hydraulic coupling devices. One coupling device of each pair houses a plurality of male plug pins which are attached to the conduits of one multi-line hose; and the other coupling device of that pair houses a plurality of female plug pins which are attached to the conduits of a second multi-line hose. The female plug pins mate with the male plug pins when the two coupling devices are attached (usually by the interengagement of complementary screw threads on their casings), thereby connecting the two multi-line hoses. The plug pins are, in each case, held within radial slots provided in a holder mounted in the casing of the coupling device. A hydraulic coupling device of this type is described in German Pat. No. 1 255 417.
The main disadvantage of this known hydraulic coupling device is that the fitting and removal of the plug pins is difficult. This arises because, when the plug pins are introduced into, or withdrawn from, the slots in the holder, they must be in alignment with the longitudinal axis of the coupling device. If the plug pins were not so aligned, introduction would be impossible (or jamming would occur during removal attempts) because of the small amount of play of the plug pins within the slots. With the known type of coupling device, this necessitates that the conduits be angled out beyond the periphery of the holder, in order that the plug pins can be introduced into, and withdrawn from, the slots in the holder. Angling of conduits, particularly where the conduits are of fairly large diameter, is difficult and impedes fitting and removal. Moreover, it is necessary to pull the holder (and the plug pins) out of the casing of the coupling device a relatively long way to permit the angling of the conduits to be carried out at all. This pulling-out operation is difficult, however, and requires the use of considerable force, particularly when the conduits are long.
The aim of the invention is to provide a hydraulic coupling device which does not suffer from these disadvantages.